both aspects are relevant. Barca needs money and Aubameyang wants to get a place in the first-team squad. because Lewandowski will certainly make Aubameyang more likely to be a substitute. Of course, it wasn't good for him. and he's got a great place at Chelsea. it was a good choice because Chelsea needs him up front.
I didn't expect, this is a surprise. Indeed, if we look at Barcelona's current squad, perhaps their top choice falls to Lewandoski. But actually I think Aubameyang could be an alternative option, looking at Lewandoski's age who probably won't be long before playing ball.
Actually Aubameyang is good, he only got into trouble with Arteta when he left Arsenal. Maybe if he is right to Chelsea then he will reunite with Tuchel while together at Dortmund. Perhaps Barcelona have a lot of consideration if they are right to release Aubameyang to Chelsea.